To manufacture a semiconductor device, various processes such as photolithography, etching, ashing, ion implantation, thin film deposition and washing are performed on a substrate to form a desired pattern on the substrate. Among these processes, the etching process is a process of removing a selected heating region of a film formed on the substrate, and wet etching and dry etching are used as the etching process. An etching apparatus using plasma is used for the dry etching off these etching processes. In general, in order to form plasma, an electromagnetic field is formed in an internal space of a chamber, and the electromagnetic field excites the process gas provided in the chamber into a plasma state.
The plasma refers to a state of an ionized gas including ions, electrons, radicals and the like. The plasma is generated by a very high temperature, a strong electric field or a RF electromagnetic field. A manufacturing process of a semiconductor device performs an etching process using the plasma. The etching process is performed by the ion particles contained in the plasma colliding with the substrate.
Meanwhile, the chamber includes a substrate processing region on which a substrate support member for supporting the substrate is disposed therein. The substrate processing region may be distinguished from other regions through a dielectric sheet disposed in the chamber. In the substrate processing process using the plasma, the dielectric sheet needs to be maintained at a constant temperature. Therefore, accurate measurement of the dielectric sheet temperature is required during the substrate processing process.
In addition, with miniaturization of the manufacturing process of semiconductor devices, the temperature of a dielectric sheet in a substrate processing apparatus is a factor which may affect a critical dimension of the manufacturing process of the semiconductor device and a profile of a pattern. Therefore, it is important to accurately monitor the temperature change of the dielectric sheet within the substrate processing apparatus in terms of reliability of the manufacturing process of the semiconductor device.